Divinyl chlorophyll a in the marine eukaryotic protist Alexandrium ostenfeldii (Dinophyceae)
2016
Rodríguez, Francisco | Garrido, José Luis | Sobrino, Cristina | Johnsen, Geir | Riobó, Pilar | Franco, José | Aamot, Inga | Ramilo, Isabel | Sanz, Noelia | Kremp, Anke
Here it is reported the first detection of DV‐chl a together with the usual chl a in the marine dinoflagellate Alexandrium ostenfeldii from the Baltic Sea. Growth response and photosynthetic parameters were examined at two irradiances (80 and 240 μmol photons m⁻² s⁻¹) and temperatures (15°C and 19°C) in a divinylic strain (AOTV‐OS20) versus a monovinylic one (AOTV‐OS16), using in vivo chl a fluorescence kinetics of PSII to characterize photosynthetic parameters by pulse amplitude modulated fluorescence, ¹⁴C assimilation rates and toxin analyses. The divinylic isolate exhibited slower growth and stronger sensitivity to high irradiance than normal chl a strain. DV‐chl a : chl a ratios decreased along time (from 11.3 to < 0.5 after 10 months) and to restore them sub‐cloning and selection of strains with highest DV‐chl a content was required. A mutation and/or epigenetic changes in the expression of divinyl reductase gene/s in A. ostenfeldii may explain this altered pigment composition. Despite quite severe limitations (reduced fitness and gradual loss of DV‐chl a content), the DV‐chl a‐containing line in A. ostenfeldii could provide a model organism in photosynthetic studies related with chl biosynthesis and evolution.
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